I would recommend UVMapper, either Pro, or Classic. Classic is a free d/l available through the link at the UVMapper forum here. You will also find tons of tutorials and UVDan, the moderator is a really nice and patient guy who's willing to help answer your questions. I've mapped almost all of my models using Classic, but I don't build too many organic or character models.  

Wings3D is a very nice free box modeler which has a nifty UV mapper built in as well. It is also handy as a file convertor, or mesh editor. You can d/l it through the link at the Wings3D forum here and you will find the folks there to be very helpful and friendly as well.